I recently bought a used Yamaha F115TLRZ. I had to replace the high pressure fuel pump in the VST to get it running. It started in my drive so took it to the lake. On the ramp it would idle for a few seconds then bogged down and die. It would not restart unless I let it sit a little while. Once it would start again throttling up would bog it down and make it die, just like idling. I am getting fuel to the VST. I am getting fuel to the rail. The injectors are making a good spray pattern. So I removed the return going into the fuel cooler and routed it to the tank. The engine is running perfectly. I don't understand why this fixed the problem. I can't find a theory of operation for the fuel system to help me pinpoint what I am missing, or any forum with someone else having the same issue. Can anyone enlighten me as to why this corrected the problem for me?
